ORTMANN: monograph of the naiades of PENNSYLVANIA. 343 



19126 Wilson, C. B. & Clark, H. W. Mussel Beds of the Cumberland River in 1911 

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1914 Wilson, C. B. & Clark, H. W. The Mussels of the Cumberland River and its 

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1917 WiNSLOW, M. L. An Annotated List of Shells from Northern Michigan {Occa- 

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1878 Witter, F. M. List of the Shells of Iowa {Quarterly Journal of Conchology, I, 

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